import java.util.Arrays;
import java.util.Scanner;

class Main1{
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while (scanner.hasNextLine()){
            String s=scanner.nextLine();
            String[] ss=s.split(" ");
            double[] doubles=new double[ss.length];
            for(int i=0;i<ss.length;i++){
                doubles[i]=Double.valueOf(ss[i]);
            }
            Arrays.sort(doubles);
            if(doubles[0]<=0){
                System.out.println("0.00");
                continue;
            }
            if(doubles.length==1){
                System.out.printf("%.2f\n",3.14*2*doubles[0]);
                continue;
            }
            if(doubles.length==2){
                System.out.printf("%.2f\n",(doubles[0]+doubles[1])*2);
                continue;
            }
            if(doubles.length==3){
                if(doubles[0]+doubles[1]>doubles[2]){
                    System.out.printf("%.2f\n",doubles[0]+doubles[1]+doubles[2]);
                }
                else System.out.println("0.00");
            }
        }
    }
}





